Homebuilt Laser Cutter Ideas

Laser-Cutter

[Wuzabear] wrote in to tell us about this “DIY Laser Cutter for PCB Stencils.” While a full BOM and step-by-step build instructions aren’t provided for the frame, pictures of the build are available, and some different options for construction are discussed. One other option that was especially interesting would be to use a ready-built RepRap or other 3D printer to act as the laser motion controller. Apparently this has been experimented with, and we’d love to see any versions that or readers have come up with!

Besides some different ideas and resources for the moving parts of the cutter, there is some information on how to hook up a laser for this purpose, as well as  for the software and calibration required. It should be noted that you should always wear the appropriate safety goggles if you’re working with a high-powered laser. Although any machine-tool can be dangerous, lasers provide some safety issues that should be treated with extreme caution.

Turning PCBs Into Art

Designing a circuit, laying out a board, and sending it off to be fabbed is so easy anyone can do it. A lot of people are, in fact, and with the traditional tools like KiCAD and Eagle, a lot of different boards look very, very similar. You could always add some cool silkscreen graphics to your board to make it stand out, but [Saar] has a better solution: it’s called PCBmodE, and it allows you to draw circuits artistically instead of the 45° angles we’ve become so accustomed to.

PCBmodE takes the parts, pads, signals, and vias for boards stored in JSON files and converts them to an SVG representation. The file is then routed (manually, but [Saar] is working on automated routing) and Gerberized so it can be sent off to a production house.

You can grab PCBmodE over on bitbucket, but right now it’s still a very early version. Vias and copper pours are working, but [Saar] has only fabbed this board so far.

Custom Boards At Home Without Etching

PCB

PC board houses are getting more accessable and less expensive all the time. Some of us are even getting very, very good at making our own circuit boards at home. There are times, though, when a project or prototype requires an extremely cheap custom board right now, something etching a custom board won’t allow. [KopfKopfKopfAffe] has a unique solution to this problem, able to create custom boards in under an hour without any nasty chemicals.

Instead of starting his build with copper-clad board, [KopfAffe] used every rapid prototyper’s friend, simple one-sided perf board. The shape of the board was milled out on a CNC machine, and both the top silk screen and bottom layer were marked off using the toner transfer method. After that, a custom circuit is just a matter of placing components and putting solder bridges between all the marked pads.

[KopfAffe] is only using this technique for single-sided boards, but we don’t see any reason why it couldn’t be employed for simple double-sided boards. This would still have the problem of making vias between the layers, but that’s still a problem with proper, home-etched double sided boards.

Hard Drive Centrifuge For Sensitizing Copper Clad Boards

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We would wager that most of the home etched PCB projects we see around here use the toner transfer method. But the next most popular technique is to use photosensitive ink which resists the etching acid once it has been exposed to light. Most people buy what are called pre-sensitized boards, but you can also get ink to make your own. [Jardirx] does this, and uses an old hard drive to apply an even layer of the light-sensitive ink.

The narration and subtitles of the video found after the break are both in Portuguese, but it’s not hard to figure out what’s going on here. He begins by using double-sided foam tape to secure the piece of copper clad board to the hard drive platters. You’ll want to center it as best as you can to keep the vibrations to a minimum. From there [Jardirx] applies a coating of the ink using a brush. The image above is what results. So as not to get ink everywhere, he then lowers a soda bottle with the bottom cut off to catch the excess. Power up the drive for a few seconds and the board will have a nice even layer ready for a trip through a UV exposure box.

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[Fran’s] PCB Etching Techniques

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We think that anyone who’s done at-home PCB fabrication will appreciate the tidiness that [Fran] maintains throughout her etching process. She recently posted a three-part video tutorial which showcases her techniques. As you can see in the screenshot above, her habits reek of top-notch laboratory skills.

Regular readers can probably guess what circuit she’s etching. It’s the test boards for her LVDC reverse engineering. She is using the toner transfer method, but in a bit different way than most home-etchers do. She uses the blue transfer paper made for the job, but before transferring it to the copper clad she uses a light box (kind of like the X-ray film viewer at the doctor’s office) to inspect for any gaps where toner did not adhere. From there she uses a heat press to apply the resist. This is a heck of a lot easier than using a clothes iron, but of course you’ve got to have one of these things on hand to do it this way.

The second part of the tutorial is embedded after the break. We chose this segment because it shows off how [Fran] built her own chemical hood. It’s a clear plastic storage container lying upside down. A work window has been cut out of the front side, and a 4-inch exhaust hose added to the top. [Fran’s] lab has a high volume low velocity fan to which it connects to whisk the fumes outside.

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Modifying A Printer For PCB Fabbing

ohgodmyeyes

The migraine-inducing image above is the product of [Rupert Hirst]’s attempts at home PCB fabrication. He’s using the toner transfer method – printing a circuit on a piece of transparency sheet with a laser printer, setting it on a piece of copper clad board, and sending the whole assembly through a laminator. It’s a fairly straightforward process, but if you can’t run a transparency sheet through a printer multiple times your etch resist won’t hold up too well. Of course the transparency sheet must be aligned each time it goes through the printer, so [Rupert] came up with a modification that ensures laser toner goes only where it’s supposed to.

[Rupert] picked up a Samsung ML-2165W laser printer for his PCB fab shop, but printing the same image multiple times on the same transparency sheet would result in unusable masks. This problem was fixed with a few plastic shims used to hang door frames and a card stock tray that ensures the transparency sheet goes through the printer the same way every time.

We saw [Rupert]’s homebrew PCB fabrication process a few weeks ago when he sent in his six channel floppy drive MIDI synth. In his build video, [Rupert] demonstrated what is possibly the cleanest toner transfer PCB we’ve seen to date. You can check out his etching process in the video after the break.

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Panelizing PCBs In Eagle

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A lot of the board houses out there including Seeed and ITead studios have a fixed size for circuit boards before the price goes up. A one-inch square board costs the same as a much larger 5cm x 5cm board, making panelized PCBs a great way to get more boards for the same amount of money. Trying to panelize a board in Eagle with copy and paste is a chore without the right tools, though, so we’re happy to see a great panelization tutorial from [Victor].

To panelize one of his boards for a PCB order, [Victor] used one of Eagle’s User Language Programs to duplicate the part names on the additional boards. After that, it was a simple matter of running a CAM job to generate the necessary Gerber files.

Of course once the boards arrive, you’ll have to cut them apart from each other. This can be done with everything from a Dremel to a hack saw to a metal shear, but we’re wondering what other Hackaday readers are using to cut up PCBs. Leave a note in the comments with your preferred method of depanelization.